The present invention relates to a process for the manufacture of artificial leather and to provision of an artificial leather having a napped suede or nubuck grain finish on natural, synthetic or semi-synthetic backing members and in particular to backing members of this type which are contacted with latex systems to bind and to provide a modified surface.
Synthetic and semi-synthetic leathers are presently known and available, possessing, in most cases, grain sides which have smooth surface characteristics. In some cases, the grain sides of known artificial leathers acquire during their manufacture a rather lightly pronounced or delicate pattern which is imitative of the side box or coating surface in which they are formed. In addition, various kinds of embossing treatments are known and employed to provide the grain sides of artificial leathers with surfaces closely resembling the appearance of natural leathers. Among such processes, for example, is the process for manufacturing patent leather. On the other hand, grain-side treatments of natural leathers include various surface treatments, generally of a purely mechanical nature, to provide a napped or nubuck grain-side surface or a suede surface. However, to achieve this type of grain side surface on artificial leathers is difficult. This difficulty is due to a large extent to the fact that in such leathers the grain sides are required to have a very fine and short nap.
Among the processes known for achieving artificial leathers which have a very fine and short nap are those employing a laminate of a foil or sheet made of a polyurethane having a suede-like grain. Also, various electrostatic processes exist in which clumps or flakes of fibers of varying lengths, made of natural or synthetic materials, are deposited on backing members which have been previously coated with an adhesive.
These known processes, however, present numerous disadvantages. For example, where polyurethane foils are employed, the foils must be adhesively bonded to the backing members while at the same time prevented from losing their elastic and rubber-like character. Consequently, the napped, nubuck or suede effect is achieved mainly by visual appearance and not by modification of the material. On the other hand, electrostatic processes involve relatively complicated technological steps, both in preparing suitable clumps or flakes of fibers and in depositing them on the backing members. Moreover, in order to achieve a uniform distribution of the clumps or flakes on the backing members, it is often necessary to repeat the deposition steps repeatedly.
The present invention provides a process which overcomes these disadvantages, and provides an improved suede-like artificial leather composition.
Other objects and advantages of the present invention will appear from the disclosure of the invention as given herein.